Apparatus for receiving a digital information signal comprising a first video signal producing images of a first size, and a second video signal producing images of a second size smaller than the first size

ABSTRACT

The invention relates to an apparatus for receiving a first and second video signal. The first video signal represents a sequence of images having a first size, and the second video signal representing a sequence of images having a second size, the second size being smaller then the first size of the images. The apparatus combines said first and second video signal so as to obtain a composite video signal suitable for displaying on a display unit. The signal combination means being adapted to combine the first and second video signal while the size of the images corresponding to the second video signal remains unchanged.

The invention relates to an apparatus for receiving a digitalinformation signal comprising at least a first and second video signal,said apparatus comprises:

-   -   receiving means for receiving said digital information signal;    -   first retrieval means for retrieving said first video signal        from the digital information signal;    -   second retrieval means for retrieving said second video signal        from the digital information signal;    -   signal combination means for combining said first and second        video signal so as to obtain a composite video signal suitable        for displaying on a display unit.        The invention further relates to record carrier carrying a        digital information signal and an apparatus for providing a        digital information signal.

An arrangement defined above is commonly known. Such an arrangement, forexample a digital TV, comprises the feature Picture in Picture (PIP) orSplit-screen. With this feature it is possible to view simultaneouslytwo different broadcast programs. Both programs are received with fullresolution. The bandwidth of the input has to be two times the bandwidthneeded to receive one program. In the case of the feature Picture inPicture, one of the two programs has to be reduced before the images ofsaid program could be combined with the other program so as to obtainthe PIP image.

Nowadays, service providers add additional video or still picture slideshow content to a video signal to enhance their product. Examples aremulti-angle feature and director commentary feature of DVD. In the firstcase one could view a scene from another direction. Both Digital TVsystems and DVD support a multi-angle feature but in both cases the usermust choose only one of the angles to view and all angles are includedat full screen resolution.

It is an object of the invention to provide an arrangement for receivinga digital signal with improved interactivity so as to enhance video withadditional video content.

The arrangement in accordance with the invention is characterized inthat characterized in that the first video signal represents a sequenceof images having a first size, and the second video signal representinga sequence of images having a second size, the second size being smallerthen the first size of the images, the signal combination means beingadapted to combine the first and second video signal while the size ofthe images corresponding to the second video signal remains unchanged.The size of an image could be defined in the number of horizontal andvertical pixels.

The invention is based on the following recognition. Up till now, theimages of two video programs transmitted in the form of an MPEGtransport stream via a record carrier or broadcast are full screen. Inthe event the two video programs are recorded on a record carrier theycould be stored in two different transport streams. To be able toproduce a PIP screen, both video programs has to be received completelyand one of the programs has to be processed to obtain the PIP-images,which has a reduced size. In the event they are read from a recordcarrier, the reading head and input circuitry should be able to read andprocess both streams simultaneously or real-time. Therefore, thesedevices should have a high bandwidth. In optical reproducing devicesthis becomes critical. Furthermore, circuitry is needed to reduce thesize of the images of one of the video programs. The images of theadditional video signal to enhance a video program (main video) withmulti-angle feature or “director's commentary” have a directrelationship with specific parts of said video program. These imageshave to be displayed simultaneously with the main video. Therefore,according to the invention the additional video signal istransmitted/recorded in a PIP-format. This has the advantage that itreduces the bandwidth needed to receive both the main video and theadditional video information. Furthermore, no special hardware/softwareis needed to reduce images of the additional video signal prior tocombining said reduced images with the main video so as to obtain thePIP-images.

This invention is a very advantageous feature for published discs asadditional video content can be added to the main video program withoutchanging the original video material. This additional video (or stillpicture slide show) content will be overlaid on top of the main video ina window that takes up usually only a small part of the screen. Thisfeature can be used in many ways depending on the content. One exampleis an enhancement of the “director's commentary” feature of DVD. In thiscase, instead of only hearing the directors voice, you could also seethe directors face, see storyboards or see ‘making of’ footage as thedirector explains the scene. For other types of content (e.g.documentaries, sports), the PIP feature can be used in different ways.The invention improves the interactivity with main video programs on apublished disc.

A further embodiment of the arrangement according to the invention ischaracterized in that the digital information signal further comprises aparameter signal indicative for the location where the second videosignal has to be overlaid on top of the first video signal, theapparatus further comprises third retrieval means for retrieving theparameter signal, the signal combination means further being adapted tooverlay the second video signal on top of the first video signal independence of said parameter.

An advantage of such a parameter is that editors has the possibility toposition the images of the second video signal in such a location in theimages of the first video signal that the images of the second videosignal only covers an un- or less important part of the images of thefirst video signal. In this way the viewer can see the relevant parts ofthe first video signal.

These and other aspects of the invention will be apparent from andelucidated by means of three embodiments with reference to the drawingsin which

Embodiments of the invention will now be described in more detail, byway of example, with reference to the drawings, in which

FIG. 1 shows an arrangement for receiving a digital information signalin accordance with the invention,

FIG. 2 shows an arrangement for providing a digital information signalin accordance with the invention.

FIG. 1 shows an apparatus 2 for receiving a digital information signalcomprising a first and second video signal. The first video signal isthe main video and the second video signal is the additional videocontent. The apparatus comprises a receiving unit 4 for receiving saiddigital information signal. The receiving unit could comprise a readingunit not shown, for reading the information signal from a recordcarrier, such as an optical disc 6. However, the receiving unit couldalso be connected to a reading unit or a set-top box 8, which is capableof retrieving both the main video and the additional video content andto provide this information in said digital information signal to theapparatus 2. The digital information signal is preferable in the form ofan MPEG transport stream. The main video is in full screen size and theadditional content is in reduced size, the size of the PIP-window.

The apparatus further comprises a first retrieval unit 10 for retrievingthe main video signal from the digital information signal and secondretrieval unit 12 for retrieving the additional video content from thedigital information signal. The main video signal and the additionalvideo information are supplied to a signal combination unit 16. Thesignal combination means is arranged for combining the main video andthe additional video content so as to obtain a composite video signalsuitable for displaying on a display unit 18.

The main video is retrieved in full resolution or full size. The imagesof the additional video content are not in full size. When these imagesare displayed on a display without any scaling they will fill only apart of the screen. In other words the additional video content has areduced resolution when displayed in full screen format. The signalcombination unit is adapted to combine the first and second video signalwithout changing the size of images of the additional video content.

Preferably the second video stream is included along with the main videostream in the multiplex on a disc. The secondary video stream will havelower resolution than the original and will be displayed as a Picture inPicture. Preferably the additional video content is multiplexed with themain video.

To control this PIP feature there are two basic approaches, one is todefine the PIP stream in the multiplex and the other is to define it inthe metadata information (PlayList or ProgramInfo).

PlayLists are known from DVD. The PlayLists are shown to the user in theUI and the user can choose to play one. The PIP feature could be definedas a separate PlayList which the user can choose. To enable this thePlayList has to indicate the elementary streams to present. To enablethis the PlayItem structure is extended to specify the Elementary Stream(indicates with program identifiers PIDs) to present and should allowindicating the PIP stream as well as the main video stream.

ProgramInfo structure is known from the Digital Video Recorder standard(DVR) and defines the audio and video PIDs in the recorded TransportStream. This structure is preferably extended to specify that certainstreams are intended as PIP streams. For example, each stream isspecified using a StreamCodingInfo table, this could be extended tospecify that a stream is a PIP stream and should be displayed over themain video if the user specifies it (and the system supports it).

In the Transport Stream the Programme Map Table indicates the elementarystreams in the multiplex. Each stream has an associated stream typeindicating if it's audio or video and the coding type. In accordance tothe invention the stream_type field allows PIP streams to be specified,for example, one of User Private values could be defined to indicate PIPstreams (e.g. one for video and one for associated audio).

The user-data in the picture header should contain the followinginformation:

-   -   Size of the PIP (pixels hor/vert)    -   Location of the PIP in the main picture (It should always be        presented at a location where the Main picture does not contain        valuable information e.g the ball/goal in a football game). The        location information may also take into account different aspect        ratios and display formats.    -   The blending with the Main picture.    -   the corresponding audio PID, to identify which audio stream in        the transport stream has to be used.

The apparatus in FIG. 1 comprises further a third retrieval unit 14 forretrieving the user-data defined above. This data is supplied to thesignal combination unit 16 to control the signal combination unit.

For a Program Stream the solution would be to reserve one (or more) ofthe video stream_ids for the PIP or indicate that that stream_id isintended as a PIP and should not be displayed as full screen video.Alternatively, reserved Stream_ids used in PES headers can be definedfor PIP streams.

In an other embodiment of the invention the first video signal isretrieved from a record carrier, such as an optical disc and the secondvideo signal is retrieved from another storage medium. Said recordingmedium carrying the first video signal could comprise links (URL's) orother suitable indicators to the location of the second video signals.Said other storage medium carrying the second video signal could be anoptical disc, or a medium, which is accessible via a wired or wirelessconnection, such as the internet or a network server. In this embodimentthe apparatus comprises a receiving unit for receiving the first videosignal and a control signal to enable said apparatus to retrieve thesecond video signal and another receiving unit for receiving the secondvideo signal in dependence of said control signal. The control signalcould comprises information where the apparatus can find the secondvideo signal or could be an application, which offers the users a menu,this could be a WEB page, which enables a user to select a second videosignal from several possible second video signals.

FIG. 2 shows an apparatus for providing a digital information signal inaccordance to the invention. The apparatus comprises a first input unit42 for receiving the main video and a second input unit 44 for receivingthe video content to be added in full screen format or full resolution.The apparatus further comprises a video signal processing unit 46arranged for reducing the size of the video content to be added so as toobtain video content in the form of PIP stream. The signal combinationunit 48 combined the main video and the PIP stream so as to obtain thedigital information signal, preferably in the form of an MPEG transportstream. The digital information signal could be transmitted or recordedon a record carrier, such as an optical disc.

Signal 50 could be supplied to the signal combination unit to include inthe digital information signal the user data, identifying which streamsare PIP streams and the location of the PIP window in the screen andother suitable PIP control information. Signal could by generatedmanually in a studio or automatically by image analysis tools. Theanalysis tools determined unimportant parts in the main video images.These part are used to display the PIP window.

Though the invention is described with reference to preferredembodiments thereof, it is to be understood that these arenon-limitative examples. Thus, various modifications are conceivable tothose skilled in the art, without departing from the scope of theinvention, as defined by the claims. Selecting the PIP feature may causea different audio track to be presented (e.g. director's commentary) orit may leave the audio unchanged (e.g. reverse angle PIP in sportsdisc). The PIP feature may appear for only specific portions of the mainvideo or it may be presented throughout the complete content.

The use of the verb “to comprise” and its conjugations does not excludethe presence of elements or steps other than those stated in a claim.Furthermore, the use of the article “a” or “an” preceding an elementdoes not exclude the presence of a plurality of such elements. In theclaims, any reference signs placed between parenthesis shall not beconstrued as limiting the scope of the claims. The invention may beimplemented by means of hardware as well as software. Several “means”may be represented by the same item of hardware. Furthermore, theinvention resides in each and every novel feature or combination offeatures.

The invention claimed is:
 1. An apparatus for receiving a digitalinformation signal comprising at least a first video signal and secondvideo signal, said apparatus comprises: a receiver for receiving saiddigital information signal; first retrieval unit for receiving saiddigital information signal and retrieving said first video signal fromthe received digital information signal; second retrieval unit forreceiving said digital information signal and retrieving said secondvideo signal from the received digital information signal; and signalcombination unit for combining said first video signal and said secondvideo signal so as to obtain a composite video signal suitable fordisplaying on a display unit, wherein the first video signal forms, ondisplay, a sequence of images having a first size, and the second videosignal forms, on display, a sequence of images having a second size, thesecond size being smaller than the first size of the images, the signalcombination unit combining the first and second video signals whilekeeping the size of the images corresponding to the second video signalunchanged, and wherein the digital information signal further comprisesa parameter signal indicative for the location where the second videosignal has to be overlaid on top of the first video signal, and theapparatus further comprises third retrieval unit for receiving saiddigital information signal and retrieving the parameter signal, thesignal combination unit overlaying the second video signal on top of thefirst video signal in dependence on said parameter signal.
 2. Theapparatus as claimed in claim 1, wherein the digital information signalis in the form of an MPEG transport stream.
 3. The apparatus as claimedin claim 1, wherein the digital information signal is recorded on arecord carrier, the receiver reading the digital information signal fromsaid record carrier.
 4. The apparatus of claim 1, wherein the receiverreceives the first video signal from a first source and receives thesecond video signal from a second source which is different from thefirst source.
 5. A record carrier in the form of a storage mediumreadable by a device, the record carrier having a digital informationsignal recorded thereon, the digital information signal comprising afirst video signal and a second video signal, wherein the first videosignal forms, on a display, a sequence of images having a firstdisplayed size, and the second video signal forms, on the display, asequence of images having a second displayed size, the second displayedsize of the images being smaller than the first displayed size, whereinthe digital information signal further comprises a parameter signalindicative for a location where the second video signal has to beoverlaid on top of the first video signal when said first and secondvideo signals are to be combined to form a composite video signal, andwherein the digital information signal further comprises a separateplaylist comprising the second video signal and items having a displayedsize smaller than the first displayed size for selection of the secondvideo signal or the items by a user for display on the display.
 6. Anapparatus for providing a digital information signal, said apparatuscomprising: an input unit for receiving a first video signal and asecond video signal, the first video signal forming, on a display, asequence of images having a first displayed size; a signal combinationunit for combining said first and second video signals so as to formsaid digital information signal; and an output unit for providing saiddigital information signal, wherein the apparatus comprises videoprocessor for processing the second video signal so as to obtain aprocessed second video signal forming, on the display, a sequence ofimages having a second displayed size, wherein the second displayed sizeis smaller than the first displayed size of the images, the signalcombination unit combining the first video signal and the processedsecond video signal while retaining all video information in the firstand processed second video signals so as to form said digitalinformation signal, and a device for generating a control signal forindicating a location where the second video signal is to be overlaid ontop of the first video signal, wherein the signal combination unitcombines the control signal with the first video signal and the secondvideo signal in forming the digital information signal, and wherein thedigital information signal further comprises a separate playlistcomprising the second video signal and items having a displayed sizesmaller than the first displayed size for selection of the second videosignal or the items by a user for display on the display.
 7. Theapparatus as claimed in claim 6, wherein the output unit writes thedigital information signal onto a record carrier.
 8. The apparatus ofclaim 6, wherein the control signal comprises information where theapparatus can find the second video signal, and an application whichoffers users a menu to enables the user to select the second videosignal from a plurality of second video signals.